Cash, credit, or Bitcoin? A Palo Alto cafe is adopting a new payment method.

Within the past several weeks, Coupa Cafe in Palo Alto became one of the only brick-and-mortar businesses in the Bay Area -- and in the world -- to start accepting Bitcoin, an online, unregulated open-source currency.

Let's say you want to buy a medium latte: you'll see the price in dollars, around $3 or $4, and the price in Bitcoin, .048 BC, which might not seem like a lot, but consider that one Bitcoin is currently trading at roughly $90.

That Bitcoin amount can change on a daily basis as the currency rate fluctuates.

The transaction takes as much time as a credit card.

“A lot of people have Bitcoins, but they don’t have a place to send it,” said Jean Paul Coupal, who owns the cafe with his mother and sister. “Now they can come and buy a cup of coffee with it.”

It’s fitting Coupa Cafe would pioneer the use of Bitcoin. For years, techies, venture capitalists and angel investors have been coming to the cafe to hash out deals. They even use the cafe to test out new software products, like crowd-sourcing food delivery.

One of the first Facebook fan pages ever was for Coupa Cafe, created by Facebook employees when their HQ used to be just around the corner.